Clasp and clasp supported dental restoration



g 3931- I c. c. KUNDE 1,819,296

CLASP AND CLA S P SUPPORTED DENTAL RESTORATION Filed May 31, 1930 A TTORNE YS Patented Aug. 18, 1931 UNITED STATES PATENT OFFICE CHARLES C. KUNDE, OF NEW YORK, N. Y., ASSIGNOB TO JULIUS ADERER INOfi, OF

' 7 NEW YORK, N. Y., A CORPORATION OF NEW YORK CLASP AND CLASP SUPPORTED DENTAL RESTORATION Application filed May 31,

This invention relates to restorations supported from abutment teeth by clasps and to the clasps used for that purpose. The object of the invention is to supply a clasp of novel'construction possessing great resiliency and adapted to be associated with a restoration in such a manner as to produce improved results. tended to partially embrace abutment teeth and to support removable bridgework or partial .dentures. The clasps in themselves are ready-made articles of merchandise. which arecustomarily associated with the restoration by dentists or dental technicians familiar with the proper manner in which such clasps should be associated or attached to the restoration in order to produce the desired results.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a 'front' view of a typical restoration with the clasps in position for use, but before the final placing of the artificial teeth. Fig. 2 is a view of the device illustrated in Fig. 1 taken from the under side of the saddle. Fig. 3 is a view similar to Fig. 1 with the artificial teeth in place. Fig. 4 is an inverted view of Fig.3. Fig. 5 illustrates the structure of Fig. 3 when associated with the abutment teeth. Fig. 6

30, is an inverted View of Fig. 5. Fig. 7 is an enassociated with the occlusal rest. Fig. 10 is a side view of Fig. 9. Fig. 11 is a sectional plan view taken on line 1111 of Fig. 9, and Fig. 12 is an enlarged cross-sectional detail view taken on line 1212 of Fig. 11.

4o. 5 In the drawings Figs. 5 and 6 showa typical example of a complete restoration in place. This type'of restoration comprises, as shown in Figs. 1 to 4, the saddle 1, the posts 2, the occlusal rests 3, the clasps 4, and the artificial teeth 2a, the artificial teeth being placed' upon and cemented to the posts 2. The clasp 4, as more clearly shown in Figs. 9 to 12, is preferably a continuous resilient wire member of acid-resisting metal or alloy bent over near the central portion to form the Clasps for such purposes are .in--

1930. Serial No. 457,906.

vertical arms 5, the two free ends of the bent wire being thereupon first bent outwardly and then inwardly at approximately right angles from the vertical arms 5 to form the relatively semi-circular clasping sections 6. Preferably the vertical arms 5 are circular in cross-section while the clasping sections 6 are flattened on their'inner surfaces as illustrated in Fig. 12, although the clasp can, of'

course, be constructed in either the round, half-round, oval, or bevelled wire or any comblnatiorrof any such shapes. The elasping sections care furthermore, in the preferred embodiment of the invention, shaped so that vertical or tortional arms 5, on the other hand, may be longer on the lingual than on thebuccal, depending on the angle of the abutment tooth to be clasped. In other ready-made articlesjof commerce, they will be made with tortional arms of the same lengths and of different lengths'and of unequal lengths, so that the dental technician canselect the one which is appropriate to the particular condition of his subject.

'words, in the manufacture of the clasps, as

In making a denture such for example as shown in Fig. 1,-a dentist usually makes a plaster impression and from that plaster impression 1 the laboratory which he uses shapes the saddle 1 to conform closely to the tissue as indicated in Fig. 7 The pins 2 are incorporated in the saddle structure and after the restoration has been finally fitted, the artificial teeth 5 are cemented upon the pins 2. Incompleting the restoration the. occlusal rest. 3 which usually constitutes an integral extension of the saddle portion of the restoration lis formed and shaped to conform with the adjacent abutment teeth 9, so that ultimately the relation between the saddle 1, the occlusal rest 3, and the abutment teeth. 9 i and the gum or tissue will represent as near a perfect and exact fit as the dentist can possibly obtain. When this perfection of fit and conformity has been determined, the clasp member 4 is soldered or cast into the restoration so as to be supported therefrom; inthe region of the bentover portion of the vertical arms 5 of the clasp as indicated at 3a in Figs. 7 and 10, so-

that the majorportion of the vertical-arms and the horizontal arms-are capable of-mov-,

ing with respect to-the restoration except at the point where the claspiis'attached beneath the occlusal rest. It will be observed that in such a construction, as the clasping-sections 6-- are spread apart in passing over the sides of the abutment teeth, they will have the benefit not only of their own resiliency, but of the tortional resiliency of the vertical arms 5. The'lresult of this combination .of resilient and tortional movements. is to increase the over-all resilient capacitv of the clasp and to furnish a tight gripping contact under both tortional and resilient effects against the outer faces of the abutment teeth. In order to achieve this result, the permanent. union betweenthe claspf and the restoration is, as stated, restricted to the upper portion of the clasp',so as to leave the vertical or .tortion arms capable "of spring movement as well as'tortional movement, also giving the horizontal terminal clasping members 6 and 7, and 6 and 8, respectively, an opportunity of moving tortionally. '0

The tortion arms 5 of the clasp are positionetLon the approximal. sides of the supporting teeth. The extensionclasping sections embrace said abutment teeth, both at the buccal and'the lingual cervical margins of the teeth. *This' feature. is a result of'the structure of the new clasp. and is the consequence of its powerful resiliency. In priorclasps the resiliency was insuliicientto enable the clasping members. to be positloned closer to the margins. of the teeth than thejunction of the cervical thi'rdof. the tooth, i. ,e. closely below the widestpart ofthe teeth. In such prior structures, .if the clasping arms'were; moved further. toward the gum l1ne,t he armswould not have sufficient resiliency'to .close upon the tooth andto hold the appliancein properpositionz- ;WVith my new clasp,;how-

ever, due to its capacity to permit proper flexure under spring and tortional influences, 1t 1s '*poss1ble to bring the :freer armsof the clasp close to the tissueas indicated in Fig 5. Thi sijresults in a. material-reduction of conspicuousness as well as-a more secure and reliableanchorage. e

Another feature nvolved in the use of the new =elasp is that it permits the entirevertical section of; the clasp, as wellnas ofthe metal which terminates. in. the occlusalrest 3, tube completelyhidden from view between the natural abutmentteeth and theadj acent artificial teeth. As indicated in' Fig. 7 the artificial tooth 2a is ground on one of its approximal sides to form the recess 10 capable of receiving the metal from which the occlusal rest 3 projects, as well as that portion of the clasp which lies between the artificial tooth and the abutment tooth. This recess must be 'of such dimensionsas to allow'for the movement of the clasp when the tortion arms 5. are spreadapart or subjected to .tortionalstrains. This means .that care should be taken to allow sufficient free space not only laterally of the arms 5;( asshown in Fig.

7) but also at the corner portion 11 of the recess 10soasto. avoid. contact or binding at those corners. WVhen the clasp is thus seated. in the recess 10, the wholeof it except the :clasping sections 6 (as shown in Figs. 5 and 6) will becompletely 'invisible while the relationbetween the naturahsu'pporting tooth and the adjacent artificial tooth can be that of an'actual contact at-their-- approximal sides.

The" result of such an" arrangement is to render the removable-ap-' pliance very much less conspicuous and bet-* ter able toreproduce the natural conditions;

. The reason. for the special shape given -to'- the end sections 7 and 8 (Fig.9) of the clasp member isto make them more readily eon- W form to the angles of the teeth. As indicated in Fig. 8, the natural abutment-tooth'9 extends somewhat at an angle fronrthe tissue so that in order to obtain a: proper grip-at,

the buccal and lingual cervical margins of the tooth, respectively, the gripping ends 7- and 8 of the clasp are required-to'be' seatedin slightly different planes.

. The wire of which the claspls made may be round in cross-section:throughout. -In the preferred constructlon, however, round wire of about :18 0119' gauge is usedand-thje.

free Tends thereof are placed in a machine "which'fiatt'ens the t-Woends to the necessary-- extent indicated in Figs; 9 and 1-2, so t-hat the r extension arms are about lt or 15 gauge.

- The thus formed resilient wire a is" then bent" at itscenter to form the verticalarmsyb,-v

'while the flattened portions are then bent at approximatelyri'ght angles to the vertical arms.5 and;are then curved to approximate semi-circles with the flat faces12 facing each which is ing or abutment tooth-is placed under; strain: I and is movedaccording to the tensionottha appliance asa whole. In the new clasp the resiliency is such that" the appliance-adjusts structure. and the tendency to break or to become distorted is reduced to a minimum.

When the new clasp is used, there is considerably less strain on the natural teeth. The new clasp, also, due to its peculiar resiliency, provides a better anchor than prior clasps. In inserting and removing the appliance, there is less friction on the natural teeth than in the. case of less resilient clasps. The free ends of the new clasp can be more readily and accurately adjusted to the shape of the natural teeth than was heretofore possible with prior ready-made clasps. This is, in part, due to the relatively small dimen sions of the clasp wire which lend themselves to easy manipulations to assure close conforming contact, as well as to the great resiliency of the clasp which assures maintenance of close conforming contact after it is once established.

In attaching the new clasp at its upper portion in the space below the occlusal rest, it is not necessary to make any special or adjusted fit as between the clasp and the denture. The clasp can be soldered in and the free ends then shaped by tools to fit accurately around the abutment teeth.

Numerous other advantages result from the use and application of the new clasp.

It is understood that in the appended claims the invention is intended to be covered with due regard to equivalent or modified structures incorporating the essence of the novel features of my invention.

I claim:

1. A clasp adapted to support a dental restoration from an abutment tooth, composed of resilient metal comprising two elongated approximately parallel closely adjacent vertical arms having free ends, said free ends being bent first outwardly and then inwardly from each of the vertical arms at approximately right angles thereto, said clasp on attachment to a restoration being held only at those portions of the vertical arms which are most remote from the free ends whereby, when the. free ends are spread apart, they will be placed under resilient as well as tortional influence.

2. A clasp of the character set forth in claim 1 in which the resilient metal of which the clasp is composed is constituted of a continuous wire bent upon itself to form the two vertical arms.

3. A clasp 0f the character set forth in claim 1 in which the vertical arms are substantially round in cross-section, while the free end sections are provided with substantial vertical flattened faces.

4. A clasp of the character set forth in claim 1 in which the free ends terminate at a distance from each other approximating the lateral extent of the approximal surface of two contiguous teeth.

5. A restoration comprising a saddle, an occlusal rest supported by the saddle, a clasp of the character defined in claim 1, and means by which the upper end only of the vertical arms of the clasp are attached below the occlusal rest.

6. A restoration comprising a saddle, an occlusal rest supported by the saddle, a clasp of the character defined in claim 1, and means which attach the upper end only of the vertical arms of the clasp below the occlusal rest and position the free ends of the clasp at the cervical margin of the abutment tooth.

7 A restoration comprising a saddle, an occlusal rest supported by the saddle, a clasp of the character defined in claim 1, an artificial tooth, a recess in the artificial tooth of sufficient dimensions to receive the vertical arms of the clasp and to permit movement thereof within said .recess and means for at taching the clasp at the upper end of the vertical arms so as to permit the same, while firmly attached to the structure, to have lateral and tortional movement in the recess as the free ends of the clasp are spread apart.

In witness whereof I have hereunto set my hand.

CHARLES C. KUNDE'. V 

